With the development of technologies of new energy vehicles, in particular pure electric vehicles, the safety of electric vehicles has drawn more and more attention from people. As a high voltage power supply component of electric vehicle, the safety of power battery is especially important. An over-load protection design of the power battery is used for improving the safety of battery pack.
For a power battery assembly of existing electric vehicles, the over-load protection of the power battery typically comprises an over-load current limiting protection based on battery management system (BMS) and a fuse protection based on fuse holder. The over-load current limiting protection detects battery temperature and current signals through the BMS, and sends an instruction to the whole vehicle control unit (VCU) when the temperature and the current are overly high. Then, the VCU sends an instruction to reduce external loads. The whole control process is long and complicated, and requires a computer to control actuator, thus presenting a risk of failure; in the fuse protection, the fuse holder generates a lot of heat in case of a large load current so as to directly melt the fuse, thus causing a mechanical circuit break.